Baking Soda is actually Bicarbonate Of Soda which is derived from the manufacture of common washing soda. Baking Soda is composed carbon and oxygen molecules which combine to form carbon dioxide gas. If a batter has sufficient acidic nature then only baking soda is needed to produce carbon dioxide.
All baking soda in the United States is mined in Green River Wyoming. The deposit was discovered in the 1930's.
When baking soda is added to a recipe it has an immediate rising action with the release of the gas which means that your oven must be preheated and your pans greased before you even combine the ingredients. Baking Soda should be added to dry ingredients first and the wet ingredients just before placing the food in the oven.
Baking soda will last for approximately 6 months if tightly covered but if your baking something special buy fresh baking soda.
I bet you didn't know that Sodium Bicarbonate is also produced in the human body to assist in maintaining the acidity (ph) level of the blood in the human body. It is also found in saliva and will neutralize plaque acids which might other wise dissolve our teeth. Another action in the body is to neutralize stomach acid so that we don't get ulcers.
John I hope I told you something about baking soda you don't know.